Transom repair

[Destroyer]

Originally Posted by SkunkBoat

Motor is on.
2 bolts were bad.
Bought 1/2" x 4" x13 thread SS bolts & Nylock nuts. The thread is coarser than what is being replaced. They are going in the bottom holes.
Any good reason to get "factory" bolts?

Coarse Threads

Coarse threads are more durable and have greater resistance to stripping and cross-threading. The height of each thread is greater than the corresponding fine thread so there is more material between each thread making flank engagement greater.

Coarse threads are less susceptible to being nicked or damaged, so they do not have to be ***8220;handled with care***8221; as much as fine threads. A nick to a fine thread can cause more of a problem proportionally due to the shallowness of the thread, e.g. gaging or assembly.

Coarse threaded fasteners install much faster than fine threaded fasteners. A ½-13 bolt assembles in 65% of the time it would take to assemble a ½-20 bolt. The ½-20 bolt advances one inch in 20 revolutions, while the ½-13 bolt advances one inch in only 13 revolutions.

Coarse threads are not affected by plating buildup as much as fine threads. The same amount of plating on a coarse thread would use up a greater amount of the plating allowance on a fine thread. Fine threads experience more gaging and assembly problems due to plating buildup than coarse threads, as there is less material between each thread flank.

When using CoilThread Locking Inserts, or other stainless steel threaded fasteners, coarse threads are much less likely to experience galling than fine threads. Fine threads have more rotations as we discussed previously and this coupled with the closer pitch diameter fits of fine threads increases the tendency for fine threads to experience thread galling.

Fine Threads

Fine threaded bolts are stronger than the corresponding coarse threaded bolts of the same hardness. This is in both tension and shear due to the fine threaded bolts having a slightly larger tensile stress area and minor diameter.

Fine threads have less tendency to loosen under vibration due to their having a smaller helix angle than coarse threads. Fine thread Locking Insert grip coils are more flexible than coarse thread insert corresponding size grip coils, and are less likely to take a set under vibration conditions.

Fine threads because of their finer pitch allow for finer adjustments in those applications that need this characteristic.

Fine threads can be more easily tapped into difficult to tap materials, and thin walled sections.

Fine threads require less tightening torque to develop equivalent preloads to the corresponding coarse thread bolt sizes.

Summary

Normally a coarse thread is specified for most industrial applications unless there is a convincing reason not to do so. Military and aerospace applications generally use coarse threads on sizes 8-32 and smaller. On metric fasteners, generally the coarse sizes are the most commonly used with the finer pitches being less readily available.

[SkunkBoat]

well, did not launch yet but motor is hooked up and running. Dash switches/fuse panel /wiring all set. I need to clean it up and get my stuff back in and organized.

Had a very hard time priming the fuel line after being all disassembled. wasted an hour squeezing that bulb every which way. Long story short, the problem was with the fuel line that is part of the primer bulb(it was a Moeller pre-made one, couple years old).
The tubing has 3 layers (grey outside/black middle/clear inside) The inside lining of the tubing was coming loose and when I pushed the tubing on a fitting, it pushed in and partially blocked the tubing. (I guess I need to take a picture.)

Another problem I'm dealing with is the steering shaft of the motor (the one the motor pivots on, not the cable). I greased the fitting and some water came out the top & bottom but then it bound up. No grease coming out the ends. Got very hard to steer. I released the pressure on the grease by removing the zerk, almost got it in the eye!!! Steers better but not great.

Service manual shows removing the steering shaft as the last step in disassemlbing the entire motor..

I have to look at it some more. I don't want to remove the motor from the transom. maybe I can cheat and take up the weight of the motor on a lift
then remove a few bolts and C clip and lift the whole thing right out of the tilt housing?

I'm sure my brother will say "spray a whole can of WD40 in the zerk hole ...!"

[SkunkBoat]

Launched and ready for fishing tomorrow.

I got my baby back!!!!!

[captpete13]

Way to go skunk! The boat looks good sitting in the slip. Still some time left for fluke and then stripers.

[bradford]

Great news!!!!

Good job Skunk!!

[Blue_Runner]

Glad you made it back on the water dude! Catchemup!

[sshyers]

I hit a sandbar and my motor also his and popped up. My top 2 motor bracket bolts got slightly pulled through the transom and cracked the fiber glass.

Does anyone have an idea on how much this might cost to get repaired by a boat marine mechanic?

Trying to decide if I should just start looking for another haul or not.